Abstract

In the last 60 years, incidental entanglement in fishing gears (so called by-catch) became the main cause of mortality worldwide for small cetaceans and is pushing several populations and species to the verge of extinction. Thus, monitoring and quantifying by-catches is an important step towards proper and sustainable management of cetacean populations. Continuous studies indicated that by-catches and directed takes of small cetaceans in Peru greatly increased since 1985. Legal measures banning cetacean takes, enforced in 1994 and 1996, ironically made monitoring highly problematic as fishers continue catching these animals but utilize or dispose of carcasses clandestinely. Hence, in locations where cetaceans are landed covertly or already butchered, molecular genetic methods can provide the only means of identification of the species, sex, and sometimes the population of each sample. Here, we generate and analyse a fragment of the mitochondrial DNA cytochrome b gene and 5 nuclear microsatellite markers from 182 meat and skin samples of unidentified small cetaceans collected at three Peruvian markets between July 2006 and April 2007. Our results, compared to past surveys, indicate that Lagenorhynchus obscurus, Phocoena spinipinnis, Tursiops truncatus, Delphinus capensis, and D. delphis continue to be caught and marketed, but that the relative incidence of P. spinipinnis is highly reduced, possibly because of population depletion. The small number of possible sampling duplicates demonstrates that a high monitoring frequency is required for a thorough evaluation of incidental catches in the area. A wide public debate on by-catch mitigation measures is greatly warranted in Peru.

Keywords

By-catch mortality Cetacean Microsatellites Mitochondrial DNA

Electronic supplementary material

The online version of this article (doi:10.1007/s10592-010-0106-8) contains supplementary material, which is available to authorized users.

Notes

Acknowledgments

This work was supported by grants from the University of Geneva (Switzerland), the Swiss National Science Foundation (FNSNF, grant 31003A_125060), the Georges and Antoine Claraz Foundation, the Ernst and Lucie Schmidheiny Foundation, and the National Fund for Scientific Research, Belgium (FNRS). Field work was possible through grants from Rufford Small Grants Foundation, Whale and Dolphin Conservation Society, Oak Foundation, Cetacean Society International, and the Cleveland MetroParks and Zoo. ACT is post-doctoral fellow at the FNRS. JCM and JAS are Overseas Research and Student Awards Scheme and University of Exeter scholarship awardees, respectively. We thank Cesar Barco, Percy Haro, Diana Vega and Celia Cáceres, of the Peruvian NGOs ProDelphinus and CEPEC for invaluable assistance in sampling and data collection.

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